Health Library

Labor

What is labor?

Labor is a series of continuous, progressive contractions of the uterus which help the cervix to open (dilate) and to thin (efface), allowing the fetus to move through the birth canal. Labor usually starts two weeks before or after the estimated date of delivery. However, no one knows exactly what triggers the onset of labor.

What are the signs of labor?

Signs of labor vary from woman to woman, as each woman experiences labor differently. Some common signs of labor may include:

Bloody show. A small amount of mucus, slightly mixed with blood, may be expelled from the vagina indicating a woman is in labor.

Contractions. Contractions (uterine muscle spasms) occurring at intervals of less than ten minutes are usually an indication that labor has begun. Contractions may become more frequent and severe as labor progresses.

Rupture of amniotic sac (bag of waters). Labor sometimes begins with amniotic fluid gushing or leaking from the vagina. Women who experience a rupture of the amniotic sac should go to the hospital immediately and contact their physician or midwife. The majority of women go into labor within hours after the amniotic sac breaks. If labor still has not begun after 24 hours, a woman may be hospitalized for labor to be induced. This step is often taken to prevent infections and delivery complications.

If a woman feels unsure if labor is beginning, she should always call her physician or midwife.

What are the different stages of labor?

Each labor is different. However, labor typically is divided into three stages:

First Stage. This is the onset of labor to complete dilation and is divided into the latent phase, when contractions are becoming more frequent (usually 5 to 20 minutes apart) and somewhat stronger, and the active phase. Women can have very strong, painful contractions during the latent phase. The cervix dilates (opens approximately three or four centimeters) and effaces (thins out). Some women may not recognize that they are in labor if their contractions are mild and irregular.

The latent phase is usually the longest and least intense phase of labor. The mother-to-be may be admitted to the hospital during this phase. Pelvic exams are performed to determine the dilatation of the cervix.

The active phase is signaled by the dilatation of the cervix from 4 to 6 centimeters. Contractions become longer, more severe, and more frequent (usually 3 to 4 minutes apart).

The third phase is called transition and is the last phase. During transition, the cervix dilates an additional 3 to 5 centimeters until the cervix has dilated fully to a total of 10 centimeters. Contractions are usually very strong, lasting 60 to 90 seconds and occurring every few minutes. Most women feel the urge to push during this phase.

In most cases, the active and transition phases are shorter than the latent phase.

Second Stage. The second stage of labor begins when the cervix is completely opened and ends with the delivery of the baby. The second stage is often referred to as the "pushing" stage. During the second stage, the woman becomes actively involved by pushing the baby through the birth canal to the outside world. When the baby's head is visible at the opening of the vagina, it is called "crowning." The second stage is shorter than the first stage, and may take between 30 minutes to three hours for a woman's first pregnancy.

Third Stage. After the baby is delivered, the new mother enters the third and final stage of labor--delivery of the placenta (the organ that has nourished the baby inside of the uterus). This stage usually lasts just a few minutes up to a half-hour. This stage involves the passage of the placenta out of the uterus and through the vagina.

Each labor experience is different and the amount of time in each stage will vary. However, most women will deliver their baby within 10 hours after being admitted into the hospital, if the labor is not induced. Labor is generally shorter for subsequent pregnancies.

Induction of labor

In some cases, labor has to be "induced," which is a process of stimulating labor to begin. The reasons for induction vary. Labor induction is not done before 39 weeks of pregnancy unless there is a problem. Some common reasons for induction include the following:

The mother and/or fetus are at risk

The pregnancy has continued too far past the due date

The mother has preeclampsia, eclampsia, or chronic high blood pressure

Administering an intravenous infusion of oxytocin (a hormone produced by the pituitary gland that stimulates contractions) or similar drug.

Rupturing (artificially) the amniotic sac (bag of waters).

Care at the hospital during labor

When a woman arrives at the hospital in labor, the nursing staff may perform a physical exam of the abdomen to determine the size and position of the fetus, and an exam of the cervix. In addition, the nursing staff may check the following:

Blood pressure

Weight

Temperature

Frequency and intensity of contractions

Fetal heart rate

Urine and blood samples

Intravenous fluids are sometimes given during labor. The intravenous line, a thin plastic tube inserted into a vein (usually in the woman's forearm), can also be used to give medications. Intravenous fluids are usually given once active labor has begun, and also are needed when a woman has epidural anesthesia.

The fetus, too, is carefully monitored during labor. A monitor may be placed over the mother's abdomen to keep track of the fetal heart rate.

What are pain management options during labor?

A woman has many options for managing the discomforts that occur during labor and the birth of her baby. Generally, mothers and their physicians or midwives want to use the safest and most effective method of pain relief for both mother and baby.

The choice will be determined by:

The woman's preference

The woman's health

The health of the fetus

The physician's or midwife's recommendation

There are three main types of pain management for labor and birth:

Nonmedicated measures. These measures provide comfort and relieve stress, sometimes called natural childbirth. Many women learn special techniques to help them feel more comfortable and in control during labor and birth. Some of these techniques include:

Relaxation. These techniques such as progressive relaxation, in which various muscle groups are relaxed in series, can help a woman detect tension and be better able to release that tension.

Touch. This may include massage or light stroking to relieve tension. A jetted bath or a shower during labor may also be effective ways to relieve pain or tension. Ask your physician or midwife before taking a tub bath in labor.

Heat or cold therapy. This is used to help relax tensed or painful areas, such as a warmed towel or a cold pack

Imagery. These technique of using the mind to form mental pictures that help create relaxed feelings.

Meditation or focused thinking. Meditation focuses on an object or task, such as breathing helps direct the mind away from the discomforts.

Breathing. These techniques use different patterns and types of breathing to help direct the mind away from the discomforts.

Positioning and movement. Many women find changing positions and moving around during labor helps relieve discomfort and may even speed labor along. Rocking in a rocking chair, sitting in the "Tailor sit" position, sitting on a special "birthing ball," walking, and swaying may be helpful to relieve discomfort. Your labor nurse, physician, or midwife can help you find comfortable positions that are also safe for you and your baby.

Analgesics. These are medications to relieve pain such as meperidine. Small amounts are generally safe during labor and are commonly used with very few complications. However, if given in large amounts or in repeated doses, analgesics can cause respiratory depression respiratory depression (slowing of the breathing center in the brain) in mothers and babies.

Anesthesia. These are medications that cause loss of sensation include pudendal block, epidural anesthesia and analgesia, spinal anesthesia and analgesia, and general anesthesia.

Local block. Anesthesia injected in the perineal area--the area between the vagina and rectum-- numbs the area for repair of a tear or episiotomy after delivery

Pudendal block. A type of local anesthesia that is injected into the vaginal area (affecting the pudendal nerve) causing complete numbness in the vaginal area without affecting the contractions of the uterus. The woman can remain active in pushing the baby through the birth canal. It is used for vaginal deliveries.

Epidural anesthesia (also called an epidural block). This anesthesia involves infusing numbing medications through a thin catheter that has been inserted into the space that surrounds the spinal cord in the lower back, causing loss of sensation of the lower body. Infusions of medications may be increased or stopped as needed. This type of anesthesia is used during labor and for vaginal and cesarean deliveries. The most common complication of epidural anesthesia is low blood pressure in the mother. Because of this, most woman need to have an intravenous infusion of fluids before epidural anesthesia is given. A risk of epidural anesthesia is a postpartum headache. It may develop if the epidural needle enters the spinal canal, rather than staying in the space around the canal. The anesthesiologist will discuss the risks, benefits, and alternatives to the various methods of pain relief with the patient.

Epidural analgesia. This is sometimes called a "walking" epidural because the medication infused through the epidural is an analgesic, which relieves pain but does not numb the body and allows movement. Combinations of medications may be used in the epidural--part analgesic, part anesthetic. The most common complication of epidural analgesia is low blood pressure in the mother. This type of anesthesia is used during labor and for vaginal deliveries. A risk of epidural analgesia is a postpartum headache. It may develop if the epidural needle enters the spinal canal, rather than staying in the space around the canal. Epidural analgesia may be used for pain relief in labor and for vaginal deliveries.

Spinal anesthesia. This type of anesthesia involves injecting a single dose of the anesthetic agent directly into the spinal fluid. Spinal anesthesia acts very quickly and causes complete loss of sensation and loss of movement of the lower body. This type of anesthesia is often used for cesarean deliveries.

Spinal analgesia. This involves injecting an analgesic medication into the spinal fluid to provide pain relief without numbing. Spinal analgesia may be used in combination with epidural anesthesia or analgesia. This may be used during labor for pain relief or for postpartum pain relief.

General anesthesia. This type of pain relief involves giving an anesthetic agent that causes the woman to go to sleep. This type of anesthesia may be used in emergency cesarean deliveries.